Shifting currents may confuse whales

Press, 24 April 1984, Page 36

Shifting currents may confuse whales

NZPA-AP Miami Confusion or weakness brought on when ocean currents shift may be to blame when otherwise healthy, mature whales are found beached, a researcher says. “For years people have thought it was suicide. I did not go for the suicide theories,” said Professor Dan O’Dell, a marine biology professor at the University of Miami, who has been studying the phenomenon for about a decade. “There is no proof.” Professor O’Dell believes ocean currents are responsible for pushing some whales and dolphins away from their normal feeding areas and into unfamiliar areas.

“The animals become confused and suffer stress. Without their usual food supply they develop vitamin deficiencies or diseases and sometimes die,” he said. “Some may be so weak they get tossed in the surf,” he said. The animals or their remains eventually washed up along the beaches, said Professor O’Dell, aged 38, who also acts as a scientific coordinator for the United

States marine mammal and sea turtle stranding and salvage network.

The Smithsonian Institution said nearly 400 whales and dolphins beached themselves last year. So far this year, there have been 42 with no reports of mass beachings. The hundreds of autopsies Professor O’Dell conducted on stranded pygmy sperm whales, often found in southeastern waters, appeared to support this ocean-currents theory, he said. The sexually mature pygmy whales (about five or six years old), had heart problems.

“The heart muscle breaks down, the circulation and kidney function follow, and they die,” he said.

Professor O’Dell said the 3m to 3.6 m whale, which feeds on squid at the edge of the Gulf Stream, either got sick and stopped feeding, or they wre taken from their food supply by something. “I feel it is current patterns, though we have not looked at enough data in enough depth to be able to say for certain,” he said. Professor O’Dell said he learned that at the same

time he received reports of whale strandings, there was a corresponding veer from the usual north-south path of the Gulf Stream to eastwest.

The movement of water could even explain the mass strandings, he said.

Whales migrate thousands of miles each year. The same animal that might be found in Newfoundland one month could end up in the Caribbean several weeks later.

“But not all strandings are alike. In tropical waters, whales often beach themselves alone, while mass strandings are more common in New England. The latest occurred on Cape cod last December and involved 22 pilot whales.”

Professor O’Dell said soipe strandings were simply the result of old age or illness or other factors unrelated to current shifts.

“It is simply because of natural processes. They are just too young or too old to go on; or perhaps they got stuck in nets,” he said.